My '75 El Camino has the electrical harness from the '77 Elco I scrapped. I should be able to figure out the AC wiring, but it's been almost 7 years Anyone have a diagram of the '77 Malibu/El Camino AC wiring ? I have one for a '76, but not sure if it's the same (??) If it IS the same, I can likely figure it out.My diagram for the '76 shows a thermo limiter and a super-heat cut-out switch in the compressor wiring, and I don't remember if mine was like that (?)

Also the diagram shows an engine thermo switch, which I believe is the little round switch that screws into the rear of the driver-side cylinder head (?) Some diagrams call it a "metal switch "...

Bill...don't know if this is of any help but, is all I could find in my 1977 GM Service Manual. Tried taking a clearer photo but, can't get a more detailed pic. I'm 99% sure the wiring is the same on '76 & '77 based on the Temp Controls being the same vs. the '75.

Do you know where the Light Blue wire connects to? I think that is the wire that is in the pic below and I didn't see a connection on the firewall harness. Its cut so I'm not sure where the other end was connected to.

pila wrote:My '75 El Camino has the electrical harness from the '77 Elco I scrapped. I should be able to figure out the AC wiring, but it's been almost 7 years Anyone have a diagram of the '77 Malibu/El Camino AC wiring ? I have one for a '76, but not sure if it's the same (??) If it IS the same, I can likely figure it out.My diagram for the '76 shows a thermo limiter and a super-heat cut-out switch in the compressor wiring, and I don't remember if mine was like that (?)

Also the diagram shows an engine thermo switch, which I believe is the little round switch that screws into the rear of the driver-side cylinder head (?) Some diagrams call it a "metal switch "...Bill

FWIW, Bill, my 73 diagram has all of the above. I'm going to guess it didn't change much through the entire generation. The really clear version is too large to post here -- PM me your email address and I'll send it to you.

Hawk03 wrote:Do you know where the Light Blue wire connects to? I think that is the wire that is in the pic below and I didn't see a connection on the firewall harness. Its cut so I'm not sure where the other end was connected to.

Looking at the diagram for the HVAC, the only LT BLU wire (ckt 72) runs from the blower switch in the cabin to the resistor pack on the HVAC case underhood. It appears to be for one of the medium fan speeds.

Looking at the diagram for the HVAC, the only LT BLU wire (ckt 72) runs from the blower switch in the cabin to the resistor pack on the HVAC case underhood. It appears to be for one of the medium fan speeds.

Do I need to connect the wire directly to the blower switch or should it connect through the firewall junction (lower drivers side)?

The blower works with power hookup directly to it, I just need to connect this wire and the system should work.